Facile fabrication of silica nanoparticles with incorporation of AIEgen and coreactant as self-enhanced electrochemiluminescence probes for sensitive immunoassay of microcystin-LR

Microcystin-LR (MC-LR) is an algae toxin that poses a serious threat to human health because of its multiorgan toxicity, genotoxicity, and carcinogenicity. Herein, we develop an electrochemiluminescent (ECL) immunosensor for MC-LR detection on the basis of aggregation-induced ECL (AIECL)-assisted self-enhancement strategy. The probe used in this assay is prepared by simultaneously encapsulating AIEgens (namely 1,1,2,2-tetra(4-carboxylbiphenyl)ethylene (H4TCBPE) and its coreactant 2-(dibutylamino)ethanol (DBAE)) into silica to form ternary H4TCBPE@SiO2-DBAE nanoparticles. DBAE can function as a catalyzer to accelerate the in situ formation of SiO2 matrix and an intracoreactant to react with H4TCBPE for the generation of an intense ECL emission as a result of shortened electron transfer pathway and decreased energy loss. We further prepare a biocompatible and electroactive Ti3C2Tx/MoS2/Au hybrid that acts as the immuosensing substrate to accelerate interfacial electron transfer and conjugate the captured antibody (Ab1). Both Ab1-coated Ti3C2Tx/MoS2/Au and antibody (Ab2)labeled H4TCBPE@SiO2-DBAE can interact with target MC-LR to obtain a sandwich immunosensor. This immunosensor enables quantitative detection of MC-LR antigen with a detection limit of 31 fg/mL and a broad linear range from 50 fg/mL to 10 ng/mL. The proposed strategy opens up a new avenue to fabricating new selfenhanced ECL emitters for sensitive monitoring of environmental microcystins.